Jaundice in Infants and Children

431 ULTRASOUND CLINICS Ultrasound Clin 1 (2006) 431–441 Jaundice in Infants and Children Marilyn J. Siegel, MD - Sonographic examination Spontaneous perforation of the - Overview of cholestatic diseases extrahepatic bile ducts - Neonatal jaundice Inspissated bile syndrome Biliary atresia - Jaundice in older infants and children Neonatal hepatitis syndrome Caroli disease Additional imaging studies to Byler disease differentiate atresia and hepatitis Hepatocellular diseases Alagille syndrome Inflammatory diseases of the biliary ducts Choledochal cyst Biliary tract obstruction - References Real-time sonography remains the screening echogenicity of the normal liver is low to medium study of choice for the evaluation of jaundice in and homogeneous, and the central portal venous infants and children and it is an important tool in vasculature is easily seen (Fig. 1). In the neonate differentiating between obstructive and nonob- and young infant, the hepatic parenchyma and re- structive causes of jaundice [1,2]. The causes of nal cortex are equally echogenic. In individuals 6 cholestasis are multiple, but the three major causes months of age and older, the liver usually is more are hepatitis, biliary atresia, and choledochal cyst. echogenic than the kidney. The patency and flow Other causes include neoplastic processes, cirrhosis, direction of the hepatic vessels should be do- and strictures. cumented with pulsed and color Doppler interroga- This article reviews the common congenital and tion. The liver and adjacent area should also be acquired causes of jaundice in the pediatric patient evaluated for evidence of end-stage liver disease, in- and describes the sonographic findings associated cluding collateral channels (varices), hepatofugal with these conditions. The role of correlative imag- flow, and ascites. ing studies is also reviewed. The diameter of the common duct should be measured on the sagittal scan to confirm the presence or absence of ductal dilatation. The upper Sonographic examination limits of the common duct should not exceed 1 The sonographic examination of infants and chil- mm in neonates, 2 mm in infants up to 1 year of dren who have jaundice includes a detailed exami- age, 4 mm in children 1 to 10 years of age, and 6 nation of the liver, bile ducts, gallbladder, and mm in adolescents and young adults [3]. The distal pancreas. Hepatic size and echotexture should be portion of the common duct is typically larger than thoroughly assessed. The right hepatic lobe should the proximal portion. Ductal size may increase by extend to or just below the right costal margin 1 mm or more during deep inspiration and the in a patient without hyperinflated lungs. The Valsalva maneuver [4]. The cystic duct in children Radiology and Pediatrics, Mallinckrodt Institute of Radiology, Washington University School of Medicine, 510 South Kingshighway Boulevard, St. Louis, MO, 63110, USA E-mail address: [email protected] 1556-858X/06/$ – see front matter ª 2006 Elsevier Inc. All rights reserved. doi:10.1016/j.cult.2006.05.010 ultrasound.theclinics.com 432 Siegel (1) neonatal and (2) older child and adolescent. In the neonate, biliary atresia, the neonatal hepatitis syndrome, and choledochal cyst are the most common causes of jaundice [7–9]. Other causes include syndromic and nonsyndromic bile duct paucity, inspissated bile syndrome, and spontaneous perforation of the extrahepatic bile duct. In older children, jaundice is most often caused by hepatocellular disease, including hepatitis and cirrhosis. Biliary tract obstruction is a less common cause of childhood jaundice. The possible causes of obstructive jaundice include choledochal cyst, cholangitis, stricture, stones, and neoplasms. The results of various laboratory tests of liver function, in conjunction with the pertinent histori- Fig. 1. Normal liver. Transverse sonogram shows ho- cal and physical findings, generally suffice to differ- mogeneous hepatic parenchyma. The echogenic por- entiate between obstructive and nonobstructive tal venous vasculature (arrows) is easily seen. The causes of jaundice. Imaging examinations are used gallbladder (GB) is distended and the wall is thin to confirm the clinical impression. In patients and hyperechoic. PV, portal vein. who have obstructive jaundice, these studies may also often show the level and cause of obstruction. Sonography is the preliminary imaging proce- is not routinely seen unless it is dilated, and then dure. If the extrahepatic ducts are well visualized usually only the distal part of the duct near its inser- by sonography and are normal in caliber and there tion into the common bile duct is seen. is no evidence of intraductal dilatation, further ra- Gallbladder size usually can be assessed subjec- diologic evaluation is rarely needed. Sonography tively, but measurements may be helpful in equivo- is supplemented by radionuclide studies using hep- cal cases. The normal gallbladder length is 1.5 to atobiliary agents (99mTc-IDA analogs) when func- 3.0 cm in neonates and young infants (younger than tional information is needed. Hepatobiliary 1 year old) and the width is approximately 1 cm. In scintigraphy currently is used primarily to confirm older children and adolescents, gallbladder length is suspected diagnoses of choledochal cysts, biliary 3 to 8 cm and width is less than 3.5 cm. The wall of atresia, and neonatal hepatitis. CT or MR imaging the gallbladder should be thin, hyperechoic, and are reserved for cases in which more anatomic de- well defined. The upper limits of wall thickness in tail is needed for surgical planning or the level the fasting state are 3 mm [5]. or cause of obstruction cannot be determined by Feeding of a fatty meal may be helpful in patients sonography [10–15]. who have enlarged gallbladders to assess cystic duct patency. In healthy individuals, maximum empty- ing of the gallbladder occurs between 45 and 60 Neonatal jaundice minutes after the fatty meal, and the mean volume Biliary atresia decreases approximately 60%. Contraction of the Biliary atresia is a rare disease with an incidence of 1 gallbladder after a fatty meal supports the diagnosis in 8,000 to 10,000 live births. It is, however, the sin- of a patent cystic duct. gle most common cause of neonatal cholestasis, ac- Pancreatic size, echotexture, and ductal size should counting for nearly 90% of the surgical causes and be evaluated. Pancreatic size increases with increas- for approximately 40% of all causes of cholestasis ing age of the child [6]. The mean cross-sectional di- [16]. The cause is unclear, but it is believed to be ameter of the pancreatic head ranges between 1 and caused by in utero inflammation that results in fail- 2 cm, the body between 0.6 and 1.1 cm, and the tail ure of the remodeling process at the hepatic hilum between 1 and 2 cm. The normal pancreas is iso- [7]. Histologically, it is characterized by absence of echoic or minimally hyperechoic compared with the extrahepatic bile ducts, proliferation of the the liver. The cross-sectional diameter of the pancre- small intrahepatic bile ducts, periportal fibrosis, atic duct should not exceed 1 to 2 mm. and occasionally multinucleated giant cells. There is a spectrum of changes, depending on the extent of the obliterative process. Complete atresia is pres- Overview of cholestatic diseases ent in 75% to 85% of cases. In the remaining cases, Causes of cholestasis vary with patient age. For this there may be patency of the gallbladder and cystic review, diseases are classified into two main classes: duct or patency of only the gallbladder. Associated Jaundice in Infants & Children 433 anomalies are common (10%–20% of patients) and include choledochal cyst, polysplenia, pre-duo- denal portal vein, azygous continuation of the infe- rior vena cava, diaphragmatic hernia, situs inversus, and hydronephrosis [16–18]. Patients who have biliary atresia and neonatal hepatitis usually present at 1 to 4 weeks of age with jaundice. Distinguishing between neonatal hepatitis and biliary atresia is important, because biliary atresia requires early surgical intervention to prevent biliary cirrhosis, whereas neonatal hepatitis is managed medically. Surgical treatment varies with the level of obstruction [7,8]. When there is extrahepatic biliary obstruction (15%– 25% of cases), a direct anastomosis between the patent portion of the extrahepatic bile duct and in- testine is performed. When there is intrahepatic Fig. 2. Biliary atresia, cord sign. Transverse sonogram biliary atresia, a Kasai hepatoportoenterostomy through the porta hepatis shows an echogenic cord (anastomosis of a segment of small bowel to the (arrowheads) anterior to the portal vein (arrow), indi- portal region) is performed [7,8,19]. The success cating fibrosis along the course of the common he- rate of the Kasai procedure is inversely propor- patic duct. tional to patient age. Bile flow can be re-estab- lished in up to 90% of infants who are younger Neonatal hepatitis syndrome than 2 months of age at the time of hepatoportoenterostomy and in approximately 50% in those The neonatal hepatitis syndrome is the term given who are 2 to 3 months. The success rate decreases to nonspecific hepatic inflammation that develops to less than 20% when surgery is performed after secondary to several different causes, including in- 90 days of age because of the presence of cirrhosis fection (cytomegalovirus, herpes simplex, toxoplas- [7–9]. Liver transplantation is often required in mosis, protozoa, syphilis), metabolic defects (alpha older infants and children who have intrahepatic 1-antitrypsin deficiency, galactosemia, glycogen biliary atresia. storage disease, tyrosinosis), and Alagille syndrome. A spectrum of findings may be seen sonograph- ically, reflecting the underlying histology. The liver size and parenchymal echogenicity may be normal or increased [1]. The intrahepatic ducts are typically not dilated. The extrahepatic duct is typically not visualized. A remnant of the extrahepatic duct, however, may be noted in the porta hepatis [20– 23]. This remnant appears as a triangular or tubu- lar echogenic structure just superior to the portal vein bifurcation.

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